1. Field of the Invention
The present invention relates to insect bait stations for use in exterminating insects, and more particularly to a prefilled bait station that is easily opened and activated for use upon insertion within a cradle.
2. Description of the Background Art
Human populations have long encountered problems co-existing with various insects, particularly ants. There are more than ten thousand species of ants, a number of which infest structures, lawns, parks, and other areas frequented by humans, as well as agriculture and crops. The various species of ants vary widely in many respects including size, color, shape, distribution, food preference, and nest locations. Many other species of ants routinely disrupt activities in homes, offices, parks, and protect homopteran pests that can impact agriculture crops and ornamental plantings. As a result, controlling insect populations is therefore necessary.
A primary means of pest control involves the use of toxicants, particularly liquid poison. The spraying of liquid poison is a common method of pest control. Spraying liquid poison, however, involves a number of inherent disadvantages. A primary disadvantage involves the risk of exposing humans to the toxic chemical formulations. Furthermore, spraying poison is often harmful to the environment and often causes damage to vegetation and other animal species in addition to the targeted pest population. In addition, liquid poison that has been applied by spraying often degrades over time and/or is washed away by rain or irrigation water thereby reducing effectiveness and requiring repeated treatment and/or the use of greater quantities. Toxicants can also leach into the soil and end up contaminating the ground water.
For these and other reasons it has been found preferable to contain liquid or gel toxicants in bait station structures that contain the poison while providing access to insects. The background art reveals a number of attempts directed to pest control. The following patents provide examples of these attempts.
4,648,201Sherman4,782,621Wissman4,793,093Gentile4,823,506Demarest et al.4,841,669Demarest et al.5,446,992Stewart5,501,033Wefler5,775,026Pearce et al.5,802,761Demarest et al.5,875,586Ballard et al.5,943,816Hyatt et al.5,943,817Miller5,953,854Hyatt5,983,558Las et al.6,041,542Payton et al.6,189,259Soller6,195,933Woodruff6,216,384Dickson et al.6,532,696Clark III, et al.
U.S. Pat. No. 4,793,093, issued to Gentile, discloses a feeding station for vermin that allows for ingress of the vermin to feed on poisoned bait held at a central portion therein. The bait is contained within a central well and ingress is facilitated by an inclined ramp leading to the chamber. A cover is joined to the top of the base member to cover the central well holding the poisoned bait.
U.S. Pat. Nos. 4,823,506 and 4,841,669, issued to Demarest et al., each disclose an insect bait device for exterminating crawling insects. The devices comprise first and second housing portions joinable to form a housing that defines generally unobstructed entry into the device by an insect. U.S. Pat. No. 5,802,761, also issued to Demarest et al., discloses a bait station including a base defining a bait-cup and a cover fastened to the base. The cover and base cooperate to form a door and walkway to admit targeted insects to enter the bait station thus gaining access to the bait cup.
U.S. Pat. No. 5,501,033, issued to Wefler, discloses a liquid delivery bait station having two reservoirs and fluid transfer systems to allow sequential delivery of two liquids. The liquids are preferably an insect attractant that is first delivered into an absorbent feeding pad and an insect toxicant that is next delivered to the absorbent pad.
U.S. Pat. No. 5,775,026, issued to Pearce et al., discloses an insect bait station for attracting and killing insects that comprises a substantially flat configuration with insecticide formulated as a solid coating on the surface of a sheet of moisture free material, and one or more breakable ampoules containing an attractant composition. The ampoules are held in a compressible portion of the housing permitting them to be manually broken to discharge their contents on command thereby releasing attractant vapors.
U.S. Pat. No. 5,875,586, issued to Ballard et al., discloses a refillable liquid bait station formed to allow access by insects, but not by larger animals. The bait station includes a transparent housing that protects the liquid bait from wind and rain and which further prevents leakage if the bait station is tumbled and/or placed in an incorrect position by use of a series of inner walls and chambers.
U.S. Pat. No. 5,943,816, issued to Hyatt et al., discloses an insect bait station for delivering a liquid toxicant. The bait station includes a reservoir, a feeding disk with capillary feeding pores, and a base that seals the feeding pores when configured in a closed position. U.S. Pat. No. 5,953,854, also issued to Hyatt, discloses a spill resistant granular bait station having a tunnel entrance leading to an interior bridged member having an inner wall leading from the bottom surface to an inner surface having an access opening in the bridge member leading to a bait source contained within the station. A cover defines a recessed portion thereon closely cooperating with the access opening in the base.
U.S. Pat. No. 6,041,542, issued to Payton et al., discloses a spill-resistant liquid bait station for dispensing liquid bait. The liquid bait is contained in a reservoir at the bottom of the bait station base and a lid is secured over the end of the base. The interior of the bait station is configured for containing the liquid bait if the bait station is inverted. Insects enter the bait station through one or more access ports and then travel through an interior passageway to the liquid bait.
U.S. Pat. No. 6,189,259, issued to Sailer, discloses an insect bait-and-switch liquid delivery apparatus for the control of insects. The apparatus includes a reservoir defining a first chamber containing a liquid attractant and a second chamber containing a liquid toxicant. A first feeding station is provided in the first chamber and a second feeding station is provided in the second chamber. A passageway connects the first and second chambers, and an access port is disposed to initially prevent or limit access of an insect to the second feeding station during an initial feeding period and the subsequently enable access to the second feeding station via the passageway after the initial feeding period.
U.S. Pat. No. 6,195,933, issued to Woodruff, discloses a bait station for delivery of liquid insecticide formed from a base having at least one feeding station and a reservoir for storing liquid beneath the base. The insecticide is transferred by capillary action from the reservoir to the feeding station via a connecting tube.
U.S. Pat. No. 6,216,384, issued to Dickson et al., discloses an insect bait station having a continuous outer wall leading from a base to an upper annular surface having a central axial recessed opening therein leading down to a bait source contained in the interior of the station. The interior of the station defines an inverted conical concave part for concentrating the bait to the lowest point of the cone in proximity with an opening in the bottom of the central axial recessed opening.
U.S. Pat. No. 6,532,696, issued to Clark III, et al., discloses a holder for liquid insect bait comprising a sealed container having a bottom portion defining contours that form reservoirs and channels wherein liquid bait may be located and flow. The device is deployed by orienting the device in a vertical configuration whereby the liquid bait flows to specified internal reservoirs, cutting an entrance opening in the container at a specified location, and placing the container in a horizontal configuration wherein the liquid bait flows to additional reservoirs accessible to the insects.
The present inventor has contributed significant advancements in the art of insecticide delivery using insect bait stations. In U.S. Pat. No. 6,871,444, the present inventor discloses a user activated, disposable insect bait station particularly adapted for use with liquid bait, including attractants and toxicants. The bait station is formed as a sealed container fabricated from two primary parts, an upper half and a lower half sealingly connected along common peripheral edges. The bait station includes first and second internal chambers. The first internal chamber contains a liquid bait reservoir wherein all of the liquid bait is stored prior to use, and the second internal chamber is adapted to function as an entrance providing insects access to the second chamber. Manual manipulation of the bait station is required for activation whereby a frangible seal is broken placing the first and second chambers in fluid communication thereby allowing liquid bait to flow into the second chamber. Further advancements relating to the bait station are disclosed in U.S. Pat. Nos. 7,310,908, 6,655,079, 6,502,348, and 6,202,341, all in the name of the present inventor. The patents identified in this paragraph are incorporated herein by reference.
While the insect bait stations disclosed in the art are generally suitable for the purposes for which they are intended, many of the bait stations are difficult to deploy, and fail to provide sufficient access to the bait, particularly as the level of the bait within the station changes over time due to evaporation, consumption, etc. A further disadvantage present in the bait station art is the failure to provide easy ingress as well as egress. The failure to provide sufficient egress is particularly problematic as it results in the accumulation of dead insects within the bait station. It has been found that dying insects give off a chemical scent warning that deters other insects from the area thereby rendering the bait station prematurely ineffective. Accordingly, there exists a need for an improved insect bait station that is prefilled, easily deployed without exposing persons to harmful chemicals, and provides improved ingress and egress even as the level of the bait changes.